1. Field of the Invention
The invention relates to the field of satellites and, in particular, to inflatable satellites.
2. Description of Related Art
Inflatable satellites are old in the art. For example, the ECHO satellite launched in the early dates of space flight was a large balloon with a reflective coating. Of course, later designs such as disclosed in U.S. Pat. No. 5,386,953 xe2x80x9cSpacecraft Designs For Satellite Communication Systemxe2x80x9d by J. R. Stuart were far more sophisticated communications satellite including an inflatable torus shaped structure incorporating an array of antennas and solar cells. However, this design does not store in a very small volume, nor is it light in weight. In addition, continued pressurization is required to insure that its shape is maintained. Thus a large supply of pressurized gas is required in order to maintain internal pressurization over a long time period. Therefore there is a need for a low cost and small size satellite that can be used for missions requiring small payloads.
Thus, it is a primary object of the invention to provide an inflatable satellite design.
It is another primary object of the invention to provide an inflatable satellite design that stores in a very small volume when un-inflated.
It is a further object of the invention to provide an inflatable satellite design that once inflated remains rigidized upon elimination of internal pressurization.
The invention is a satellite assembly suitable for use with small payloads. In detail, the invention includes a foldable flexible sheet. A housing for containing the payload of the satellite is mounted at the center of the sheet. A plurality of inflatable tubular members is coupled at a first end to the housing and along it""s length to the sheet having a second end terminating at the periphery of the sheet, the tubular elements movable from a collapsed condition to an inflated condition. A plurality of flat solar panels is attached to the sheet in a manner allowing the sheet to be folded.
A system is included for internally pressurizing the tubular members such that they become rigid. In addition, it is preferable to include a system for rigidizing the tubular members after inflation such that should internal pressure be lost, the tubular members remain rigid. Typically, this is accomplished by coating the interior of the tubular members with an ultra-violet curing resin, such that when the satellite is placed in orbit, exposure to ultra-violet radiation from the sun cures the resin coating, thereby rigidizing the tubular members.
Preferably the solar arrays are mounted about a portion of the foldable flexible sheet connected to the housing. Another approach is to have the solar arrays comprise a series of rectangular shaped panels mounted in a space relationship such that the foldable flexible sheet is foldable along the spaces between the rectangular shaped panels.
The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.